Electric space heater and method of making



0a. 12, 1948. E, SM"... 2,450,921

ELECTRIC S PACE HEATERS AND METHOD OF MAKING Filed May 4-, 1946 2 Sheets-Sheet 1 ll I I I INVENTOR, W Joy/v [AWZJff/WU/ BY I5 ATTORNEY.

Oct. 12, 1948. J. E. SMITH 2,450,921

ELECTRIC SPACE HEATERS AND METHOD OF MAKING Filed May 4, 1946 2 Sheets-Sheet 2 IN V EN TOR.

A TTORN E Y.

Patented Oct. 12, 1948 ELECTRIC SPACE HEATER AND METHOD OF MAKING John Ernest Smith, Plainfield, N. .l.

Application May 4, 1946, Serial. No. 657,278

8 Claims. (Cl. 219-38) My invention relates to electric space heaters and to methods of making them, particularly as related to dark or non-glow heaters.

Such heaters have definite advantages over glow heaters, such as elimination of fire hazards and other dangers, the method and cost of sup-- porting the glowing elements, and other factors.

It has heretofore been attempted to insulate or enclose resistors in space heaters adapted to give dark heat, but such former attempts have failed to sufliciently overcome the retardation to the heat caused by faulty material, processing and assembly, and have air gaps, undue thicknesses of insulation and other defects rendering the former heaters ineflicient.

Among the objects of my invention are to provide a dark and non-glow heater in which the resistor or heating means proper is enclosed by insulating medium and the heater is processed and constructed to primaril reduce the heat retardation of the medium and assembly to substantially a minimum, and secondly to so distribute or radiate the increased heat obtained as to obtain a substantially improved structure.

Another object of my invention is to provide a heater which makes more efficient use of electrical energy in heating air.

Another object of my invention is to provide a heater of the above indicated type, in which heated air is circulated freely and in substantial volume, without the aid of a fan or other extraneous air circulating means, although the use thereof is not precluded.

Another object of my invention is to provide a heater unit of simple parts few in number, which are rugged and easy to assemble.

Another object of my invention is to provide a combined resistor and radiator unit which is adaptable to ready mounting in or on casings or supporting structures of various kinds.

Another object of my invention is to provide a heater construction in which a surrounding casing may be located close to the heater core and yet remain sufficiently cool to the touch that there is no danger of injury from contact therewith, and also the unit may be picked up and carried about notwithstanding hours of continuous use.

Another object of my invention is to provide a heater ensemble which is light in weight, readily portable for easy movement from place to place, and small in size whereby it may be placed in any of many convenient places in homes or ofiices for storage during warm weather or at any other time when its use is not desired.

Another object of my invention is to provide a device of the above indicated character that is simple and durable in construction, economical to manufacture, and effective in its operation.

With such objects in view, as well as other advantages which may be incident to a utilization of the improvement, the invention comprises the elements and combinations hereinafter set forth and claimed, with the understanding that the several necessary elements constituting the same may be varied in proportion, arrangement and texture, without departing from the spirit and scope of the invention.

To make the invention more clearly understood, means are shown in the accompanying drawings for carrying the same into practical effect, without limiting the improvements to the particular constructions which, for the purpose of explanation, are made the subject of illustration.

In the drawings:

Figure 1 is a perspective view of a space heater embodying my invention;

Fig. 2 is an exploded perspective View of the structure of Fig. 1;

Fig. 3 is a vertical section, enlarged, taken substantially along the line 3-3 of Fig. 1; and

Fig. 4 is a fragmentary horizontal section, taken substantially along the line 4-4 of Fig. 3.

Referring particularly to Figs. 1 and 2, the example of the invention therein shown comprises, in general, end supports [0, end plates l2 and I4, and side plates [6, enclosing a combined heater radiator unit l8.

The end supports Ill, in this instance, are made of strap metal bent to inverted substantially U- shape to form legs which are turned inwardly at the bottoms to provide feet I l to which heat insulating shoes l3 may be fastened.

The end plates l2 and I4 are similar to the eX- tent that they are each made of thin sheet metal pressed to shallow dish shape and having an inturned edge flange 20. The latter flange has parallel vertical sides and rounded top fitting the end suports l0, and may have a rounded bot tom portion. Each end plate has an intermediate outwardly pressed portion 22, which is referred to later, and an inwardly flanged somewhat crescent shape hand-hold opening 24 near the top of the plate. End plate I 4 differs from end plate l2 only in the addition of an inwardly flanged opening 26 near the bottom of end plate 14, and through which electrical terminals proing inwardly sloping top and bottom edge margins H, and may have decorative and reinforcing fiutes or ribs 28.

Referring also to Figs. 3 and 4, the unit 18 comprises, in general, a heater core 32, radiator fins 3d, and upper and lower supporting brackets 38 at each end of the unit. The core 32, in

this instance, comprises two parallel rod-like.

elements 38, of ceramic or refractory electrical insulating material, in each of which is embedded a resistor coil til, of any desired value, connected at each end to a pin 62, one end of each pin 42 is embedded. in the rod 38 and the other end protrudes from the rod, this outer end being screw threaded. At one end of the core, the ins 42 are connected to each other, as by a connector M Fig. 4, and at the other end of the core the pins are connected respectively to depending conducting straps 45 on which are mounted terminal pins 6-! which, upon assembly,

fins may have variou shapes and in one form which I have found highly satisfactory the fins have one-third greater dimension vertically than horizontally. Each fin is provided, at a lower central portion, with a square, or other polygonal openings 45, see Fig. 3. At an intermediate portion of at least one, and in this case of all, of the polygon sides, each opening 46 has an offset recess 48 for a purpose to be hereinafter described.

The heater element rods 38 are embedded in a body 59, in this instance, of cast aluminum, which material extends through the openings 46 and the recesses 48 in the fins, and the body is of such a diameter as to embed also a portion of each fin in the area around the opening 4 the fins being spaced apart by portion of the body, as indicated at 52.

The above detailed unit l8 may be processed as follows:

The coils 40, with the pins 42 fixed in place, are completely embedded in the refractory material of the rods 38 while this material is soft, and in a wet state. These rods are then dried to the hard state, with gases and moisture driven out, and are jigged relative to the fins 34 in the relation shown, with a mold in position for forming the body at. Molten aluminum is then poured into the mold to cover all of the rods 38 and to fill the polygonal openings 46 and the recesses 48 of the fins, and to form the body 50 with the spacer portions 52. Thus there is produced a unitary structure of an aluminum body in which are embedded the heater rods 38 and the fin 34.

Since the body 59 and fins 34 are both of aluminum, this molding process may be caused to fuse the body and the fins together to a greater or less extent, and because it is not desirable to completely fuse the fin material at its point of attachment to the body 55, such fusing as takes place is controlled so as to be less than complete but sufficient to provide a good heat bond between the fins and body, The contraction of the bod 58 causes it to grip the rods 38 tightly, so that no heat loss is caused by reason of air gaps between the body and the rods, and the same order of contraction occurs between the fins nd body to reduce to a minimum losses due to heat transfer to the fins.

The polygonal openings 46 and/or the recess 48 are provided as reinforcement against breakage of the bond between the fins and the body 50, and so that the fins may not be displaced about the axis of the body 50. The recesses 48 act as the slots in substantially key and slot connections, in which the portions of the body 50 fitting the recesses 48 act as the keys. Obviously, if projections were substituted for the recesses 48, similar results would be provided, in which the rojections would be the keys for slits in the body 50.

In the assembly of the apparatus the brackets 36 are riveted or Otherwise connected to the two end fins 34 before or after the above described production of the unit I8. The brackets extend beyond the side edges of the fins and have out turned end portions, and the end fins may be of heavier gauge metal than the intermediat fins 34, if desired. The entire assembly may be completed by the placing of only eight screws or bolts 52, a indicated. During this operation, the end plates l2 and I4 are placed in the supports III with the supports overlying the flanges 20, the side plates l6 are placed in register with and against the out-turned ends of brackets 36, and the end plates are slipped over the ends of the side plates and brackets so that these ends are inside of and next to the flanges 20. With the parts thus positioned, they are rigidly secured together by four screws or bolts 52 at each end, as indicated.

The casing in this case is formed merely by the side and end plates which are rigidly secured to the supporting legs [0 and also to the finned heater unit Ill, The rigid connection of the casing to the brackets 35 is possible because the end fins are sufficiently flexible to allow for expansions and contractions without the provision of slip joints or the like. Furthermore, by fastening the brackets 36 to the end fins the high heat of the resistance element and the surrounding aluminum body is not communicated to the casing.

The proportioning of the parts is such that the finned heater unit i8 is disposed above the feet i3 by a distance suflicient to avoid undue heating of the fioor beneath the unit and to insure a free flow of cold air into the bottom of the casing without drawing in dust from the floor. The side plates l6 are tapered inwardly at the bottom to adjacent the fins to insure the cold air entering the finned portion. The somewhat direct heating of the aluminum body 50 and of the fins will intensively heat the air between the fins to provide an upward draft, the heated air rising through the casing and for a substantial distance thereabove thus producing a circulation of air in the room without the use of a fan.

As will be seen from the drawings the side and end plates of the casing are spaced only a short distance from the sides and ends of the finned unit, but this distance is sufficient to allow a free circulation of air along the interior surfaces of the plates, with the result that the casing is kept relatively cool to the touch at all times, Even after long periods of continuous heating operation, the heater may be picked up by means of the hand-hold 24 and carried about without danger of discomfort to or burning of the fingers. Again, the inwardly sloping top flanges I! of the side plates deflect the air rising along the side plates l6 inwardly toward the fins 34 to commingle with the intensively heated air rising between the fins, thus insuring that all air passin through the casing will be heated. It will also be noted that the tops of flanges 20 of the end plates l2 and I4 are slightly above the tops of the fins and the bracing of these flanges with the support l protects the fins from damage.

The fins 34 may be equi-spaced along the rod or body 50, or if desired, the end fins may be spaced a slightly greater distance from the remainder of the fins so that a greater volume of air may pass therebetween and the air thus will not be so intensively heated around these end fins, and there will be less heating of the supports l0 and the end plates l2 and 14.

- The outwardly pressed portions 22 of each of the end plates l2 and I4 are provided opposite the ends of the heater core 32 to provide space for the flow of air around this portion of the end plates and prevent over-heating thereof. The shape of the casing and supports with flat sides and rounded top insures that should the heater accidentally fall over it will come to rest on one of the cool sides and with the exposed top portions of the fins out of engagement with the floor or surface on which the heater is used.

The terminal pins are provided in this ex ample for the reception of the plug of an ordinary cord set which in turn connects to a wall socket outlet for the electric current, and the brace 49 takes up the pressure of the insertions of the plug upon the terminal pins 41. These terminal pins could beomitted and the wires of the electric supply cord could be permanently attached to either the pins 41 or to the pins 42, if desired.

The device is simple, economical in construction and operation, safe, ornamental, rugged, durable, of few parts, easily assembled, portable, and more effective in its heat giving property to an extent rendering the invention a distinct advance in its field.

I claim:

1. In an electrical space heater, a heating core comprising an aluminum body enclosing a resistance element and having a plurality of spaced apart fins held in and by said body, terminals extending from one end of said body, brackets secured to the end fins of said core respectively, and :a casing comprising parallel side plates enclosing side edges of said fins, end plates having inturned flange portions and enclosing the ends of said finned heating core, supporting legs for the heater and positioned along said flange portions, the side plates and flange portions interfitting, and screw means securing together the side plates, the supporting legs, the flange portions and the brackets whereby the sides and ends of the heating core are enclosed and the bottom and top are open to cause circulation of air into the bottom of the casing, upwardly through the fin spaces and out of the top of the casing.

2. In an electrical space heater, a heating core comprising an aluminum body enclosing a resistance element and having a plurality of spaced apart fins held in and by said body, terminals extending from one end of said body, pairs of brackets secured near the tops and bottoms of the end fins of said core respectively, and a casing comprising parallel side plates enclosing side edges of said fins, end plates having inturned flange portions and enclosing the ends of said finned heating core, supporting legs for the heater and positioned along said flange portions, portions of the side plates and the flange portions overlapping, and screw means extending through the supporting legs, the overlapping side plate and flange portions and securing the same to the brackets whereby the sides and ends of the heating core are enclosed and the bottom and top are open to cause circulation of air into the bottom of the casing, upwardly through the fin spaces and out of the top of the casing.

3. In an electrical space heater, a heating core comprising aluminum body enclosing a resistance element and having a plurality of spaced apart fins held in and by said body, terminals extending from one end of said body, supports for the core held in and by said body at the opposite ends thereof and having projecting portions, and a casing comprising parallel side plates enclosing side edges of said fins, end plates enclosing the ends of'said finned heating core, supporting legs, and screw means securing the side plates, the end plates and the legs to said projecting portions whereby the sides and ends of the heating core are enclosed and the bottom and top are open to cause circulation of air into the bottom of the casing, upwardly through the fin spaces and out of the top of the casing.

l. In an electrical space heater, a heating core comprising an aluminum body enclosing a resistance element and having a plurality of spaced apart fins held in and by said body, terminals extending from one end of said body, flexible supporting plates held by said body at the opposite ends thereof, projecting means secured to said plates, and a casing comprising parallel side plates enclosing side edges of said fins, end plat-es enclosing the ends of said finned heating core, supporting legs, and screw means securing the side plates, the end plates and the legs to said projecting means whereby the sides and ends of the heating core are enclosed and the bottom and top are open to cause circulation of air into the bottom of the casing, upwardly through the fin spaces and out of the top of the casing.

5. In an electrical space heater, a heating core comprising an aluminum body enclosing a resistance element and having a plurality of spaced apart fins held in and by said body, terminals extending from one end of said body, supports for the core held in and by said body at the opposite ends thereof and having projecting portions, and a casing comprising parallel side plates enclosing side edges of said fins, end plates enclosing the ends of said finned heating core, supporting legs, and screw means securing the side plates, the end plates and the legs to said projecting portions with the side and end plates spaced from the heating core to allow air to circulate around the plates to maintain the same cool, and hand hold means on each of the end plates near the top thereof.

6. In an electrical space heater, a heating core comprising an aluminum body enclosing a resistance element and having a plurality of spaced apart fins held in and by said body, terminals extending from one end of said body, supports for the core held by said body at the opposite ends thereof and having projecting means thereon, and a casing comprising parallel side plates enclosing side edges of said fins, end plates enclosing the ends of said finned heating core, supporting legs, and screw means securing the side plates, the end plates and the legs to said projecting portions with the side and end plates spaced from the heating core to allow air to circulate around the plates to maintain the same cool, and the tops and bottoms of the side plates being sloped inwardly to direct the air into the area occupied by the fins.

7. In an electrical space heater, a heating core comprising an aluminum body enclosing a resistance element and having a plurality of spaced apart fins held in and by said body, terminals extending from one end of said body, supports for the core held by said body at the opposite ends thereof and having projecting means thereon, and a casing comprising parallel side plates enclosing side edges of said fins, the top and bottom portions of the plates tapering inwardly toward the fins, cup-shaped end plates co-extensive with the end fins respectively, strap-like members surrounding the end plates on three sides and extending therebelow to form supporting legs, portions of the side plates and of the projecting means extending into the cupshaped end plates, and screw means securing together the strap members, the end and side plates and said projecting means.

8. In an electrical space heater, a heating core comprising an aluminum body enclosing a resistance element and having a plurality of spaced apart fins held in and by said body, terminals connected to said resistance element and extending from one end of said body, extension connectors fastened to said terminals, plug receiving terminals on said connectors, means supporting and bracing said connectors, supports for the core held by said body at the opposite ends thereof and having projecting means thereon, a casing enclosing the sides and ends of said fins and secured to said projecting means and supporting legs attached to said casing, the casing having an opening in one end thereof through which the plug receiving pins are accessible, and hand hold carrying means on each end of the casing near the top thereof.

JOHN ERNEST SMITH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

